Temperature compensated element and uses thereof in isolating a wellbore

Abstract

A time actuated element includes a mandrel, a housing coupled to the mandrel, the housing defining a fluid expansion chamber. A piston is positioned within the fluid expansion chamber. A thermally expanding fluid is positioned within the fluid expansion chamber. An end ring coupled to the piston slides along the mandrel in response to a sliding of the piston. A packer having a first end and a second end, the first end adapted to slide along the mandrel in response to a sliding of the end ring, and the second end fixedly coupled to the mandrel, so that a sliding of the first end of the packer toward the second end causes the packer element to decrease in length and increase in radius.

The invention claimed is: 
     
       1. A temperature compensated element comprising:
 a mandrel, the mandrel being generally tubular and having a central axis and an exterior cylindrical surface; 
 a housing coupled to the mandrel, the housing defining a fluid expansion chamber between an inner wall of the housing and the exterior cylindrical surface of the mandrel; 
 a piston positioned about the mandrel, the piston having a piston head positioned within the fluid expansion chamber and adapted to slide along the mandrel, the piston head forming a seal against the housing and the mandrel to enclose the fluid expansion chamber; 
 a thermally expanding fluid positioned within the fluid expansion chamber; 
 an end ring positioned about the mandrel, the end ring coupled to the piston, the end ring adapted to slide along the mandrel in response to a sliding of the piston; and 
 a packer including a packer element coupled to the exterior cylindrical surface of the mandrel, the packer having a first end and a second end, the first end adapted to slide along the mandrel in response to a sliding of the end ring, and the second end fixedly coupled to the mandrel, so that a sliding of the first end of the packer toward the second end causes the packer element to decrease in length and increase in radius. 
 
     
     
       2. The temperature compensated element of  claim 1 , further comprising:
 a body lock ring adapted to slide along the mandrel in response to a sliding of the piston, the body lock ring having at least one tooth; and 
 at least one wicker formed on an outer surface of the mandrel adapted to engage the at least one tooth of the body lock ring when the piston, end ring, and the first end of the packer have traveled a selected distance along the mandrel. 
 
     
     
       3. The temperature compensated element of  claim 1 , further comprising a pressure relief apparatus adapted to, at a selected threshold pressure, allow at least some of the thermally expanding fluid to flow out from the fluid expansion chamber. 
     
     
       4. The temperature compensated element of  claim 3 , wherein the pressure relief apparatus comprises a rupture disc positioned in the wall of the housing, the rupture disc adapted to mechanically fail when the pressure of the thermally expanding fluid positioned within the fluid expansion chamber reaches the selected threshold pressure. 
     
     
       5. The temperature compensated element of  claim 1 , wherein the packer element is formed from a swellable material. 
     
     
       6. The temperature compensated element of  claim 1 , wherein the packer element is formed from an elastomeric material. 
     
     
       7. The temperature compensated element of  claim 1 , wherein the packer further comprises a plurality of slats positioned at the first end and the second end of the packer element adapted to form an extrusion barrier for the packer element. 
     
     
       8. A method of isolating a section of wellbore comprising:
 providing a temperature compensated element, the temperature compensated element including:
 a mandrel, the mandrel being generally tubular and having a central axis and an exterior cylindrical surface; 
 a housing coupled to the mandrel, the housing defining a fluid expansion chamber between an inner wall of the housing and the exterior cylindrical surface of the mandrel; 
 a piston positioned about the mandrel, the piston having a piston head positioned within the fluid expansion chamber and adapted to slide along the mandrel, the piston head forming a seal against the housing and the mandrel to enclose the fluid expansion chamber; 
 a thermally expanding fluid positioned within the fluid expansion chamber; 
 an end ring positioned about the mandrel, the end ring coupled to the piston, the end ring adapted to slide along the mandrel in response to a sliding of the piston; and 
 a packer including a packer element coupled to the exterior cylindrical surface of the mandrel, the packer having a first end and a second end, the first end adapted to slide along the mandrel in response to a sliding of the end ring, and the second end fixedly coupled to the mandrel; 
 
 coupling the temperature compensated element to a downhole tubular assembly; 
 running the downhole tubular assembly into a wellbore; 
 heating the downhole tubular assembly; 
 expanding the thermally expanding fluid, causing the piston, end ring, and first end of the packer to move along mandrel so that the packer element decreases in length and increases in radius, defining an actuated position; and 
 contacting the wellbore with an outer surface of the packer. 
 
     
     
       9. The method of  claim 8 , wherein the temperature compensated element further comprises:
 a body lock ring adapted to slide along the mandrel in response to a sliding of the piston, the body lock ring having at least one tooth; and 
 at least one wicker formed on an outer surface of the mandrel adapted to engage the at least one tooth of the body lock ring when the piston, end ring, and the first end of the packer have traveled a selected distance along the mandrel; 
 and the method further comprises:
 locking the packer in the actuated position. 
 
 
     
     
       10. The method of  claim 8 , wherein the temperature compensated element further comprises a pressure relief apparatus adapted to, at a selected threshold pressure, allow at least some of the thermally expanding fluid to flow out from the fluid expansion chamber. 
     
     
       11. The method of  claim 10 , wherein the pressure release apparatus comprises a rupture disc positioned in the wall of the housing, the rupture disc adapted to mechanically fail when the pressure of the thermally expanding fluid positioned within the fluid expansion chamber reaches a selected threshold pressure. 
     
     
       12. The method of  claim 8 , wherein the heating operation comprises injecting steam into the downhole tubular. 
     
     
       13. The method of  claim 8 , wherein the heating operation comprises flowing a higher temperature fluid through the downhole tubular. 
     
     
       14. The method of  claim 8 , wherein the thermally expanding fluid is heated to between 200° F. and 900° F. 
     
     
       15. The method of  claim 8 , wherein the thermally expanding fluid reaches a pressure of between 500 psi and 4000 psi. 
     
     
       16. The method of  claim 8 , wherein the packer element is formed from a swellable material, and the method further comprises swelling the packer element with swelling fluids in the wellbore.